Dryer for tobacco or the like



Nov. 13 1962 E. FALKE ETAL DRYER FOR TOBACCO OR THE LIKE Filed March 14, 1960 Uited 3,063,159 DRYER FUR TORACCO OR THE LIKE Erik Falke, Alvsjo, and 0101": G. Karlsson, Stockholm,

Sweden, assignors to Arenco Aktiebolag, Stockholm,

Sweden, a joint-stock company of Sweden Filed Mar. 14, 1%0, Ser. No. 14,828 Claims priority, application Sweden Mar. 20, 1959 4 Claims. (Cl. 34-62) for drying air and a bottom which has an air pcrvious sector defining a drying zone in the drums, an outlet for the dried material defining a discharge zone in the drum and a solid sector defining a trap zone in the drum, means for supplying drying air through the pervious sector into the drying zone of the drum, an impeller rotatable about the axis of the drum above its bottom and having vanes projecting into the said zones, forming together with the drum vertical compartments separated by the vanes and having sectional areas increasing in the upward direction from the bottom end and means for rotating the impeller in the direction such that its vanes sweep the drying zone, discharge zone and trap zone in that order.

In the accompanying drawing is shown, by way of example only, one construction in accordance with the invention.

In the drawing:

FIGURE 1 is a vertical axial section of a drying apparatus embodying the invention,

FIGURES 2 and 3 are horizontal sections on the lines 2-2 and 3-3-, respectively, of FIGURE 1, and

FIGURE 4 is a vertical section of part of the device on the line 44-of FIGURE 2.

Referring to the drawing, the apparatus comprises cylindrical drum 1 consisting of sheet metal, externally thermally insulated and mounted on a base 2. The drum 1 has at its top an inlet 3 for tobacco, an inlet 4 provided with a heating element, not shown, for fresh air and an outlet 5 for used drying air which outlet is connected to the suction side of a fan, not shown. T o the base 2 is secured a vertical tube 6 positioned axially in the drum 1 and enclosed concentrically .by another tube '7 which forms the hub of an impeller including eight radial impeller vanes consisting of plates 8 to the outer edges of which are secured flexible strips 19 sealingly engaging the inside surface of the cylindrical drum 1. The tube '7 is provided with an outside frusto-conical flange 7 forming together with the tube 7 and the vanes 8 a number of vertical compartments, separated by the varies, with sectional areas increasing in the upward direction from the bottom end. The impeller hub 7 is supported on the tube 6 by means of a roller bearing 9 and is provided with a sprocket 10 for its continuous rotation by means of a chain 16 driven by a motor 17.

The bottom end of the tube '6 is connected to the suction side of a fan 11 the pressure side of which is connected to a chamber 12 provided with a draught valve 13 adjustable from outside the apparatus. Beneath the bottom edges of the impeller vanes 8 the housing 1 is provided with a bottom divided into several sectors and an opening which are arranged in a certain sequence in the direction of rotation of the impeller 7, 8 as indicated by an arrow in FIGURES 2 and 3. The rotor compartments between adjacent impeller vanes 8, thus, are movable in a number of fixed zones I-IV defined by the fixed bottom sectors and bottom opening in the housing. One of said bottom sectors consists of a perforated plate, sieve or lattice 15 located close to the bottom edges of the impeller vanes 8 and forming the bottom of a drying zone I as well as the top of the chamber 12' from which air is forced through the drying zone I. The inlet 3 for the tobacco mass is located above the bottom 15 immediately to the right of a trap zone IV adapted to prevent the tobacco mass from discharging rearwardly as described hereinafter. In FIGURE 1, the inlet 3 is shown in section for convenience of illustration but in fact it lies behind the inlet 4 and outlet 5 as seen in this FIGURE. The top of the drying zone I is defined by a sieve 20 consisting of a wire network. The drying zone I joins a cooling zone II which has a perforated bottom or lattice 21 coplanar with the bottom 15 and is adjacent a discharge zone III of which the bottom is an outlet 18 for the dried and cooled tobacco. Between the discharge zone III and the drying zone I the drum 1 includes the trap zone IV which has a solid horizontal bottom sector 14 joining and being coplanar with the bottom 15 of the drying zone and located closely below the bottom edges of the impeller vanes 8. From FIGURES 2 and 3 it is evident that the peripheral width of the cooling zone II is equal to the peripheral width of a rotor compartment between two adjacent impeller vanes 8 and that the peripheral width of the trap zone IV is twice the width of such a compartment which ensures that the zones I and 111 can never communicate with each other through any such compartment moving over the trap zone bottom 14. Thereby any reverse flow of tobacco from the drying zone I to the outlet zone III will be prevented.

Below the bottom 21 of the cooling zone II there is a chamber 25 separated from' the air chamber 12 by a vertical partition 26 and having a fan 22 which sucks atmospheric air through openings 23 in the cylindrical wall of the drum 1 and forces the air upwardly through the chamber 25 and a valve 24, adjustable from outside the apparatus, and further through the bottom sector 21 so that the tobacco is cooled in the zone II from which the air will escape through the sieve 20 together with the drying air from the zone I.

The tobacco introduced through the inlet 3 is moved by the vanes 8 of the continuously revolving impeller in a curved path in the direction of the arrow (FIGURES 2 and 3) through the drying zone I in which hot drying air, blown upwardly through the air pervious bottom sector 15, is forced through the tobacco mass whereby it has a tendency to elevate the tobacco or at least to decrease the sliding friction of the tobacco upon the sector 15. Also in the cooling zone II the sliding friction of the tobacco mass upon the bottom sector 21 will be eliminated or decreased by the flow of air upwardly through it. Part of the air flowing out of the sieve 20 will escape through the outlet 5 and the remainder will be recirculated through the tube 6 and fan 11 for repeated use in the drying zone I.

It will be appreciated that the apparatus can be employed for drying other shredded, fibrous, granular or similar materials.

We claim:

1. In a device for drying tobacco or the like, an upright housing having a cylindrical wall and inlets and outlets for tobacco and drying air, an upright rotor rotatably mounted in said housing and having air impervious impeller vanes, sealingly engaging the inside of said wall of the housing, said housing having fixed bottom sectors defining a plurality of zones arranged seriatim in the rotary direction of said rotor and including a drying zone having an air pervious bottom immediately below said vanes and communicating through said bottom with a supply of drying air, a tobacco discharge zone having a bottom outlet for dried tobacco, and a trap zone between said discharge zone and said drying zone adapted to prevent any reverse flow of tobacco from the drying zone to the discharge zone, said rotor having means toward its bottom portion providing an upwardly increasing area and said air supply having means for adjusting the air flow to a value at which the tobacco is elevated from the bottom or at least the sliding friction upon the bottom is decreased.

2. In a device for drying tobacco or the like, an upright housing having a cylindrical wall and inlets and outlets for tobacco and drying air, an upright rotor rotatably mounted in said housing and having air impervious impeller vanes, sealingly engaging the inside of said wall of the housing, said housing having fixed bottom sectors defining a plurality of zones arranged seriatim in the rotary direction of said rotor and comprising a drying zone having an air pervious bottom immediately below said vanes and communicating through said bottom with a supply of drying air, a tobacco discharge zone having a bottom outlet for dried tobacco, and a trap zone located between said discharge zone and said drying zone adapted to prevent any reverse flow of tobacco from the drying zone to the discharge zone and having an air impervious bottom closely below said vanes, said rotor having means toward its bottom portion providing an upwardly increasing area and said air supply having means for adjusting the air flow to a value at which the tobacco is elevated from the bottom or at least the sliding friction upon the bottom is decreased.

3. In a device for drying tobacco or the like, an upright housing having a cylindrical wall and inlets and outlets for tobacco and drying air, an upright rotor rotatably mounted in said housing and having air impervious impeller vanes sealingly engaging the inside of said wall of the housing, said housing having fixed bottom sectors defining a plurality of zones arranged seriatim in the rotary direction of said rotor and comprising a drying zone having an air pervious bottom immediately below said vanes and communicating through said bottom with a supply of drying air, a cooling zone having an air pervious bottom immediately below said vanes and communicating therethrough with a supply of cooling air, a tobacco discharge zone having a bottom outlet for dried tobacco, and a trap zone between said discharge zone and said drying zone adapted to prevent any reverse flow of tobacco from the drying zone to the discharge zone, said rotor having means toward its bottom portion providing an upwardly increasing area and said drying air supply and said cooling air supply having means for adjusting the air flows to a value at which the tobacco is elevated from the bottom or at least the sliding friction upon the bottom is decreased.

4. In a device for drying tobacco or the like, an upright housing having a cylindrical wall and inlets and outlets for tobacco and drying air, an upright rotor rotatably mounted in said housing and having air impervious impeller vanes sealingly engaging the inside of said wall of the housing, said housing having fixed bottom sectors defining a plurality of zones arranged seriatim in the rotary direction of said rotor and including a drying zone having an air pervious bottom immediately below said vanes and communicating through said bottom with a supply of drying air, a tobacco discharge zone having a bottom outlet for dried tobacco, and a trap zone between said discharge zone and said drying zone adapted to prevent any reverse flow of tobacco from the drying zone to the discharge zone said rotor having means toward its bottom portion providing an upwardly increasing area and said air supply having means for adjusting the air flow to a value at which the tobacco is elevated from the bottom or at least the sliding friction upon the bottom is decreased and said housing having a return passage for supplying fresh drying air to said drying zone having an air pervious top wall and communicating through said top wall with an outlet for consumed drying air and also with said return passage.

References Cited in the file of this patent UNITED STATES PATENTS 1,868,512 Ahlmann July 26, 1932 2,256,017 Curran Sept. 16, 1941 2,392,283 Ferre Jan. 1, 1946 2,748,497 Berg et al. June 5, 1956 2,869,249 Kamp Jan. 20, 1959 FOREIGN PATENTS 506,260 Great Britain May 22, 1939 549,131 Germany Apr. 23, 1932 

